dw_1984
Newly Enlightened
I just found this over at canadiandriver.com
http://www.canadiandriver.com/news/030429-4.htm
Quite interesting.
http://www.canadiandriver.com/news/030429-4.htm
Quite interesting.
Audi & Ford to use Luxeon LEDs as headlights
- Thread starter dw_1984
- Start date
geepondy
Flashlight Enthusiast
They don't really give details. I wonder how many and what kind? As much as I love my new Space Needle II, I don't think it would quite suffice as an automobile headlight.
Wow... sounds really cool! I wonder how the "general population" would adapt to cars lacking headlights as we know them today?
-Mike
-Mike
highlandsun
Enlightened
Hm... 120 lumens per 5W LED, right? And I'm replacing my stock 60/55W H4 bulbs that produce 1650/1000 lumens. It's a close call; 14 5W LEDs for 1680 lumens at 70W, or 1440 lumens at 60W. So the halogen high beam still has a slight efficiency advantage. On low beams, 8 5W LEDs for 960 lumens at 40W, the LED has the efficiency advantage.
Compared to 3200 lumens at 35W (43W with ballast) for HID, it's still no contest.
But the idea of a horizontal light bar kinda reminds me of Tron or that funky AutoMan TV show... Would be neat. You'd need a special projector-type lens for each LED to provide a horizontal cutoff for the low beams, but aside from that you wouldn't need much in the way of optics, reflectors, etc...
Compared to 3200 lumens at 35W (43W with ballast) for HID, it's still no contest.
But the idea of a horizontal light bar kinda reminds me of Tron or that funky AutoMan TV show... Would be neat. You'd need a special projector-type lens for each LED to provide a horizontal cutoff for the low beams, but aside from that you wouldn't need much in the way of optics, reflectors, etc...
Rothrandir
Flashaholic
wonder how they plan on heatsinking all of those? /ubbthreads/images/graemlins/grin.gif
likely some kind of fluid cooling... /ubbthreads/images/graemlins/grin.gif
likely some kind of fluid cooling... /ubbthreads/images/graemlins/grin.gif
Floating Spots
Enlightened
I'm probably wrong, but.....
In the light output equation, don't forget about output color. This seems to have a strong effect on perceived brightness. The LEDs could possibly have a lower lumen output and appear brighter. This comes from the increased color temp
In the light output equation, don't forget about output color. This seems to have a strong effect on perceived brightness. The LEDs could possibly have a lower lumen output and appear brighter. This comes from the increased color temp
highlandsun
Enlightened
Psychological perception of color/brightness is irrelevant here. The light that emits fewer photons will simply have a shorter effective range.
For example, you have a 1650 lumen lamp and a 1440 lumen lamp, both shining on an object 10 meters away. By the Inverse Square law, the amount of light hitting the object is proportional to 1/10^2, (inverse of the square of the distance). For the sake of this example, we'll ignore the constant factor and call this 16.5 and 14.4 lumens, respectively. The light hitting the object then has to reflect back to your eye. So on the roundtrip it's reduced by another factor of 100: .165 and .144 lumens, respectively. At a particular distance, the amount of light returning to your eye will fall below the cutoff threshold of visual perception. This threshold distance will be farther with the brighter light, simply because there are more photons flying around that will hit targets and return to your eye than with the dimmer light.
In this example, assuming your eye had a minimum threshold of .15 lumens, then an object 10 meters away would be dimly visible with the 1650 lumen light, and totally invisible with the 1440 lumen light. Obviously these numbers bear no relation to reality, but the principle is clear.
OK, color temperature isn't totally irrelevant - the human eye is more sensitive to yellow light than blue. It takes more photons of bluer, higher color temperature light to produce a detectable signal in your optic nerve than it does of yellow. So a 1440 lumen bluish-white LED light will illuminate much much less than a 1650 lumen yellowish halogen light.
For example, you have a 1650 lumen lamp and a 1440 lumen lamp, both shining on an object 10 meters away. By the Inverse Square law, the amount of light hitting the object is proportional to 1/10^2, (inverse of the square of the distance). For the sake of this example, we'll ignore the constant factor and call this 16.5 and 14.4 lumens, respectively. The light hitting the object then has to reflect back to your eye. So on the roundtrip it's reduced by another factor of 100: .165 and .144 lumens, respectively. At a particular distance, the amount of light returning to your eye will fall below the cutoff threshold of visual perception. This threshold distance will be farther with the brighter light, simply because there are more photons flying around that will hit targets and return to your eye than with the dimmer light.
In this example, assuming your eye had a minimum threshold of .15 lumens, then an object 10 meters away would be dimly visible with the 1650 lumen light, and totally invisible with the 1440 lumen light. Obviously these numbers bear no relation to reality, but the principle is clear.
OK, color temperature isn't totally irrelevant - the human eye is more sensitive to yellow light than blue. It takes more photons of bluer, higher color temperature light to produce a detectable signal in your optic nerve than it does of yellow. So a 1440 lumen bluish-white LED light will illuminate much much less than a 1650 lumen yellowish halogen light.
yclo
Flashaholic*
Rothrandir
Flashaholic
wow!
that doesn't look good.... /ubbthreads/images/graemlins/frown.gif
those also look slightly greenish to me.
some shots from other angles would be nice...
that doesn't look good.... /ubbthreads/images/graemlins/frown.gif
those also look slightly greenish to me.
some shots from other angles would be nice...
